I think you nailed it for me with having to confront out best selves and their absence. It's why I keep thinking of this George Orwell verse where he cursed his own cynicism upon meeting an idealistic young soldier in Barcelona (hat tip to Hitchens):
And a hat tip to you for sharing this poetry, which so perfectly expresses the feelings some of us have reading about Aaron's life, and seeing his smile in photos.
For the fly-blown words that make me spew
Still in his ears were holy,
And he was born knowing what I had learned
Out of books and slowly.
Later on he ends:
But the thing I saw in your face
No power can disinherit:
No bomb that ever burst
Shatters the crystal spirit.